Internal combustion engine with supercharger

Abstract

The compressor of a forced induction device is provided in the intake passage of an internal combustion engine. An introduction passage for introducing purge gas into the intake passage is connected to the intake passage. A bent portion is provided at a position of the intake passage that is upstream of the compressor. The curvature of the bent portion in the direction in which the intake passage extends is greater than the curvatures of the portions of the intake passage that are located upstream and downstream of the bent portion. The introduction passage is connected to a part of the bent portion that is on the inner side of the bending direction.

The invention claimed is: 
     
       1. An internal combustion engine with a forced induction device, comprising:
 a forced induction device, which includes a compressor arranged in an intake passage, the compressor including a compressor wheel arranged inside the compressor; and 
 an introduction passage, which is connected to the intake passage to introduce external gas to the intake passage, wherein 
 the intake passage includes a bent portion, which is a component separate from the compressor and is located at a position that is adjacent to the compressor and is upstream of the compressor in a direction of intake air flow, 
 a curvature of the bent portion in an extending direction of the intake passage is greater than curvatures of portions of the intake passage upstream and downstream of the bent portion in the direction of the intake air flow, and 
 when, in a direction in which a rotational axis of the compressor wheel extends, a direction toward the bent portion from the compressor wheel is defined as a positive direction and a direction toward the compressor wheel from the bent portion is defined as a negative direction, an upstream section of the bent portion in the direction of the intake air flow extends in a form in which intake air flows in a direction including a positive direction component and a downstream section of the bent portion in the direction of the intake air flow extends in a form in which intake air flows in a direction including a negative direction component, and 
 the introduction passage is connected to a part of the bent portion that is on an inner side in a bending direction, wherein the introduction passage has an opening that opens in the intake passage and faces in the positive direction. 
 
     
     
       2. The internal combustion engine with a forced induction device according to  claim 1 , wherein
 the intake passage includes an upstream passage, which configures a part of the intake passage upstream of the compressor in the direction of the intake air flow, and 
 the upstream passage includes a joint portion, which is connected to the compressor, at a downstream end in the direction of the intake air flow and the bent portion at a position adjacent to the joint portion. 
 
     
     
       3. The internal combustion engine with a forced induction device according to  claim 1 , wherein the bent portion is configured to form an area where a flow velocity of intake air is higher than that in surrounding parts at an interior of the part of the bent portion on the inner side in the bending direction. 
     
     
       4. The internal combustion engine with a forced induction device according to  claim 1 , wherein the bent portion is configured to form an area where a pressure is lower than that in the surrounding parts at an interior of the part of the bent portion on the inner side in the bending direction. 
     
     
       5. The internal combustion engine with a forced induction device according to  claim 1 , wherein the internal combustion engine is configured to introduce the external gas into the intake passage by using a difference between an internal pressure of a part of the bent portion to which the introduction passage is connected and an internal pressure of a part of the introduction passage into which the external gas flows. 
     
     
       6. The internal combustion engine with a forced induction device according to  claim 1 , wherein
 the internal combustion engine includes a fuel tank that stores fuel and a canister that adsorbs fuel vapor generated in the fuel tank, 
 the introduction passage connects the intake passage to the canister, and 
 the external gas is purge gas including the fuel vapor. 
 
     
     
       7. The internal combustion engine with a forced induction device according to  claim 1 , wherein the bent portion has a circular cross-sectional shape, and a radius of curvature of the bent portion in the extending direction of the intake passage is less than or equal to an inner diameter of the bent portion. 
     
     
       8. The internal combustion engine with a forced induction device according to  claim 1 , wherein
 the internal combustion engine includes a first introduction passage, which is connected to a part of the intake passage downstream of the compressor in the direction of the intake air flow for introducing the external gas to this part, and a second introduction passage, which is connected to a part of the intake passage upstream of the compressor in the direction of the intake air flow to introduce the external gas to this part, 
 the introduction passage connected to the part on the inner side is the second introduction passage, and 
 the curvature of the bent portion in the extending direction of the intake passage is greater than a curvature of a part of the intake passage to which the first introduction passage is connected. 
 
     
     
       9. The internal combustion engine with a forced induction device according to  claim 1 , wherein, if an imaginary line perpendicular to the rotational axis and tangent to an inner surface of the inner side section is drawn, the part of the bent portion to which the introduction passage is connected is located at a contact point where the imaginary line contacts the inner surface. 
     
     
       10. The internal combustion engine with a forced induction device according to  claim 1 , wherein the opening of the introduction passage faces in a direction intersecting the direction of the intake air flow in the introduction passage. 
     
     
       11. The internal combustion engine with a forced induction device according to  claim 6 , wherein the external gas from the canister is introduced into the bent portion in the positive direction.